Method For Producing An Endoscope, And Such An Endoscope

ABSTRACT

A method for producing an endoscope that comprises an endoscope head and an optic tube, comprises the steps of providing the endoscope head, providing the optic tube, and pushing a proximal end area of the optic tube into a distal end area of the endoscope head. The distal end area of the endoscope head is press-fitted with the proximal end area of the optic tube.

CROSS REFERENCE TO FOREIGN APPLICATION

The present application claims priority of German patent application No.10 2006 030 521.3 filed on Jul. 1, 2006.

BACKGROUND OF THE INVENTION

The invention relates to a method for producing an endoscope, theendoscope comprising an endoscope head and an optic tube.

Such a method, and an endoscope produced by this method, are generallyknown.

Endoscopes are mainly used in minimally invasive surgery in order toexamine body cavities or hollow organs. For this purpose, an endoscopecomprises an endoscope head, on whose distal end an elongate endoscopeshaft is mounted that comprises an optic tube. Connector pieces, for anexternal lighting source and irrigation/suction lines, and an eyepiececan be provided on the endoscope head. By way of the connector piece forthe lighting source, light is coupled into an optical waveguide systemextending through the endoscope head and the endoscope shaft and isguided to the distal end of the endoscope shaft. The endoscope alsocomprises an optics system for imaging purposes. The imaging optics canbe made from optical fibres, rod lenses or the like, but can alsoinclude an image sensor with electrical signal transmission.

Depending on the material of the endoscope shaft, endoscopes can be maderigid or flexible. A rigid endoscope has a shaft made from anon-flexible material, for example stainless steel or metal.

To examine a cavity of the body, a distal end area of the endoscope isintroduced into the latter, while the endoscope head, and the part ofthe endoscope shaft not inserted into the body cavity, remain outsidethe body.

The production of an endoscope comprises, among other things, connectinga proximal end area of the shaft to a distal end area of the endoscopehead.

Known methods involve preparing the endoscope head and the optic tube ofthe endoscope and pushing the two parts into one another in such a waythat the optic tube is received with its proximal end area in the distalend area of the endoscope head. The contact surfaces of both end areasare connected to one another by soldering, welding or adhesive bonding.

A disadvantage of these known methods is that connecting the endoscopehead and the optic tube is technically very complicated. In theendoscope production process, suitable machines have to be provided thatpermit welding, soldering or adhesive bonding of the contact surfaces ofthe endoscope head and of the optic tube. Moreover, these known methodsof connecting the endoscope head to the optic tube require a great dealof time. In particular, when bonding the two endoscope parts to oneanother, care must be taken to ensure that the optic tube and theendoscope head are held in a fixed position until the adhesive hasdried.

Another disadvantage of these methods is the difficulty in keeping theoptic tube and the endoscope head exactly positioned relative to oneanother during the production process, such that the length of theendoscope is reproducible. If the resulting overall length of theproduced endoscope deviates just slightly from the desired length, thisdifference in length has to be taken into account in the design of theoptical waveguide system and the imaging optics.

In the known production methods by means of welding and soldering, afurther disadvantage is that, during the production process, heatdevelops in the area of the connecting site between the two endoscopeparts. The heating of the material of the optic tube can cause saidmaterial to become brittle, thus reducing the strength of the optic tubein the area where it is affected by heat, with the result that the optictube may already break under the effect of slight flexural stresses.

A further disadvantage is that, in endoscopes that are produced by theknown methods, the connection between the endoscope head and the optictube is not stable. If, during an operation, the optic tube is subjectedto a considerable leverage on account of a flexural stress, it ispossible that the endoscope will break at the connecting site, i.e. thewelding, soldering or adhesive bonding site, between the endoscope headand the optic tube.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to remedy thissituation and to make available a method that is of the type mentionedat the outset and that permits a technically simple and stableconnection between the endoscope head and the optic tube.

It is also an object of the present invention to make available anendoscope of the type mentioned at the outset, in which the endoscopehead is of a simple construction and is connected in a stable manner tothe optic tube.

According to an aspect to the invention, a method for producing anendoscope, the endoscope comprising an endoscope head and an optic tube,is provided, the method comprising the steps of providing the endoscopehead, providing the optic tube, pushing a proximal end area of the optictube into a distal end area of the endoscope head, and press-fitting thedistal end area of the endoscope head with the proximal end area of theoptic tube.

According to another aspect of the invention, an endoscope is provided,comprising an endoscope head and an optic tube, wherein a proximal endarea of the optic tube is press-fitted with a distal end area of theendoscope head.

The method according to the invention and the endoscope according to theinvention permit a technically very simple connection between theendoscope head and the optic tube. Press-fitting the two endoscope partstogether advantageously requires no further auxiliaries, for examplesoldering tin or adhesive. Moreover, the method according to theinvention can be carried out in less time than soldering, welding oradhesive bonding of the endoscope head to the optic tube. Therefore,during production of the endoscope, it is possible to omit process stepssuch as cooling or drying of the connecting site between the endoscopehead and the optic tube.

Also, by press-fitting the optic tube with the endoscope head, whichpressing operation can be carried out cold and without heating, nomaterial weakness is caused by the effect of heat, as does occur in thecase of welding or soldering.

A further advantage of the method according to the invention compared tothe known methods is the fact that the connection between the optic tubeand the endoscope head is stable, and remains so over the course oftime. Since the two endoscope parts are pressed together, the endoscopeis not sensitive to external influences, such as water. Consequently,the optic tube does not come loose, not even after a large number ofcleaning processes of the endoscope, with the result that expensiverepair work is avoided.

The pressing together of the endoscope head and optic tube also permitsa stable connection between both parts. In this way, the endoscopeadvantageously withstands even considerable flexural stresses of theoptic tube that generate a considerable leverage on the optic tube.

In a preferred embodiment, the proximal end area of the optic tube ispress-fitted by axial compressing.

This measure represents a constructionally simple pressing of the optictube onto the endoscope head. Since the wall thickness of the optic tubeis smaller than that of the endoscope head, the optic tube is moresuitable for an axial compressing process than is the endoscope head fora crimping process.

In another preferred embodiment, the optic tube is held in an axiallyfixed position during the pressing operation, and an axial force in thedirection of a distal end area of the optic tube is exerted on theproximal end area of the optic tube.

This measure has the advantage that the press-fitting of the optic tubewith the endoscope head is achieved in a simple manner in that theinserted optic tube is held at the distal end of the endoscope head andan axial force, which acts in the direction of the distal end of theoptic tube, is exerted on it at the same time. The proximial end area ofthe optic tube is thereby axially compressed and press-fitted with theendoscope head.

In another preferred embodiment, the axial force is provided by apressing tool, in particular a mandrel.

This measure represents a technically simple possibility of generatingthe axial force acting on the optic tube. In contrast to the knownmethods, the outlay in terms of tools is much less.

In another preferred embodiment, the distal end area of the endoscopehead is provided on its inside with a circumferential recess into whichmaterial of the optic tube flows with a form fit during the pressingoperation.

This measure has the advantage that the optic tube is held in an axiallyparticularly secured position in the endoscope head, because material ofthe optic tube engages in the recess of the endoscope head. Tensileforces and pressure forces on the optic tube in the axial direction donot lead to a change in position of the optic tube relative to theendoscope head.

In another preferred embodiment, the circumferential recess is providedas a groove extending about the full circumference.

This measure has the advantage that, because of this design of therecess, a particularly large amount of material can engage in therecess. The connection of the endoscope head to the optic tube istherefore particularly stable.

In another preferred embodiment, the distal end area of the endoscopehead is provided with at least one circumferentially limited cavity intowhich material of the optic tube flows with a form fit during thepressing operation.

This measure has the advantage that the material pushed into thecircumferentially limited cavity ensures that the optic tube cannot turnrelative to the endoscope head about its longitudinal axis. In this way,the optic tube is secured against rotation in a simple manner.

In another preferred embodiment, a proximal end of the optic tube isadditionally widened in a trumpet shape.

This measure has the advantage that the proximal end of the optic tubepoints outwards and away from the longitudinal axis of the optic tube.If, during subsequent assembly work, optical fibres are introducedthrough the optic tube and the endoscope head, these are advantageouslyprevented from damage, for example from kinking or breaking.

In another preferred embodiment, the distal end area of the endoscopehead is adhesively bonded to the proximal end area of the optic tubeafter the pressing operation.

This measure has the advantage that the endoscope is sealed againstexternal influences, for example water. However, in contrast to theknown methods, the adhesive does not have to apply the adhesion forcefor the secure connection between optic tube and endoscope head, suchthat the adhesion site does not represent a predetermined break point.

Further advantages and features will become clear from the followingdescription and from the attached drawing.

It will be appreciated that the aforementioned features and those stillto be explained below can be used not only in the cited combinations,but also in other combinations or singly, without departing from thescope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described and explained in more detail below on thebasis of a number of selected illustrative embodiments and withreference to the attached drawing, in which:

FIG. 1 shows a side view of an endoscope;

FIG. 2 shows an optic tube (in cutaway view) and an endoscope head inlongitudinal section at the start of a method for producing theendoscope;

FIG. 3 shows the optic tube and the endoscope head from FIG. 2 in afurther method step of the production method;

FIG. 4 shows the endoscope head and the optic tube from FIG. 3 with apressing tool in a further method step of the production method;

FIG. 5 shows the endoscope head, the optic tube and the pressing toolfrom FIG. 4 in a further method step of the production method;

FIG. 6 shows the endoscope head, the optic tube and the pressing toolfrom FIG. 5 in a further method step of the production method;

FIG. 7 shows the endoscope head and the optic tube from FIG. 6 and afurther pressing tool in a further method step of the production method;

FIG. 8 shows the endoscope head, the optic tube and the further pressingtool from FIG. 7 in a further method step of the production method; and

FIG. 9 shows the endoscope head in a cross section along the line I-I inFIG. 8.

DETAILED DESCRIPTION OF PREFERRED EXEMPLARY EMBODIMENTS

An endoscope designated by the general reference number 10 is shown inFIG. 1. The endoscope 10 comprises an endoscope head 12 and an endoscopeshaft 14.

Such an endoscope 10 is used, for example, in minimally invasive surgeryfor examining body cavities or hollow organs. The distal end of theendoscope 10 is introduced into an opening in the body, such that atleast the endoscope head 12 remains outside the body.

The endoscope shaft 14 comprises an elongate optic tube 16 whoseproximal end area 18 is connected to a distal end area 20 of theendoscope head 12. The optic tube 16 is preferably designed as acylinder-shaped hollow cylinder with a thin wall.

A connector piece 22, for an external lighting source, and an eyepiece24 are arranged on the endoscope head 12. The endoscope 10 alsoaccommodates an optical waveguide system that extends from the connectorpiece 22 to a distal end area 26 of the optic tube 16 and is made up ofoptical fibres. The optical waveguide system is used to illuminate anoperating site within the opening in the body. The endoscope 10 alsoaccommodates an imaging system that extends from the eyepiece 24 to thedistal end area 26 of the optic tube 16. The imaging system can compriseoptical fibres, rod lenses, or also an image sensor with electricalsignal transmission.

The endoscope 10 is preferably rigid, the optic tube 16 being made fromnon-flexible materials, for example steel or metal.

In a method for producing the endoscope 10, the optic tube 16 and theendoscope head 12 are provided in a first method step (see FIG. 2). Atits distal end area 20, the endoscope head 12 has a circumferentialrecess 28 on its inside, and at least one circumferentially limitedcavity 30.

The recess 28 is preferably designed as a groove 32 that extends aboutthe full circumference in the distal end area 20 of the endoscope head12. The cavity 30 can either be arranged directly on a part of therecess 28 or can be arranged spatially separate from the latter in thedistal end area 20 of the endoscope head 12. Moreover, the cavity 30 canbe set deeper in relation to the recess 28, as seen in the radialdirection of the distal end area 20 of the endoscope head 12.

An external diameter 34 of the optic tube 16 is dimensioned such that itis slightly smaller than an internal diameter 36 of the distal end area20 of the endoscope head 12.

In a further method step, as is shown in FIG. 3, the proximal end area18 of the optic tube 16 is pushed in a direction of an arrow 38 into thedistal end area 20 of the endoscope head 12. In doing so, an outersurface 40 of the optic tube 16 touches an inner surface 42 of theendoscope head 12, or the outer surface 40 of the optic tube 16 isspaced slightly apart from the inner surface 42 of the distal end area20 of the endoscope head 12. Moreover, the proximal end area 18 of theoptic tube 16 is pushed so far into the distal end area 20 of theendoscope head 12 that at least a proximal end 44 of the optic tube 16extends past the recess 28 and the cavity 30.

FIGS. 4-8 show the distal end area 20 of the endoscope head 12 and theproximal end area 18 of the optic tube 16 being pressed together.

The optic tube 16, whose proximal end area 18 is pushed into the distalend area 20 of the endoscope head 12, is held in an axially fixedposition in respect of tensile forces and pressure forces acting in theaxial direction of the optic tube 16 (see FIG. 4). For this purpose, theoptic tube 16 is clamped in a holding device 46. Such a holding device46 can, for example, have two jaws 48, 50, which engage on the outersurface 40 of the inserted optic tube 16 distally of the distal end area20 of the endoscope head 12. The two jaws 48, 50 either touch the distalend area 20 of the endoscope head 12 or are spaced slightly apart fromit. The jaws 48, 50 of the holding device 46 are shown in FIG. 4,whereas, for reasons of clarity, they are not shown in FIGS. 5-8.

An axial force is exerted on the proximal end area 18 of the optic tube16 in the direction of an arrow 52. The axial force is generated bymeans of a pressing tool 54, which is guided from the proximal directionthrough the endoscope head 12 into the optic tube 16.

The pressing tool 54 can preferably be designed as a cylindrical mandrel56. The pressing tool 54 narrows in a step shape at a distal end 58,such that an external diameter 60 of the distal end 58 of the pressingtool 54 is slightly smaller than an internal diameter 62 of the optictube 16. Moreover, in the area of the step-shaped narrowing, thepressing tool 54 has a plane surface 64 that preferably extends aboutits full circumference and that is transverse to a longitudinal axis 66of the pressing tool 54, and on which the proximal end 44 of the optictube 16 comes to lie on the full circumference. The distal end 58 of thepressing tool 54 is preferably of such a length that the pressing tool54 extends past the recess 28 and the bulge 30 when in a fully insertedstate, i.e. when the plane surface 64 touches the proximal end 44 of theoptic tube 16.

As is shown in FIG. 5, the proximal end area 18 of the optic tube 16 isaxially compressed by the axial force in such a way that axiallycompressed material is forced radially outwards. This is especially thecase when the distal end 58 of the pressing tool 54 extends past therecess 28 and the cavity 30 and thus prevents a radially inwardlydirected movement of the buckled material. Material of the proximal endarea 18 of the optic tube 16 thus engages with a form fit in the recess28 while the optic tube 16 is press-fitted with the endoscope head 12.The engagement of the material of the optic tube 16 into the recess 28permits a secure axial positioning of the optic tube 16 relative to theendoscope head 12.

The pressing action also causes material of the optic tube 16 to engagein the cavity 30 (see FIG. 6). This ensures that the optic tube 16 isnot able to turn relative to the endoscope head 12 about itslongitudinal axis.

As is shown in FIG. 7, the proximal end 44 of the optic tube 16 is alsowidened in a trumpet shape, such that the external diameter 34 of theoptic tube 16 increases at this location. The proximal end 44 of theoptic tube 16 points outwards and away from a longitudinal axis of theoptic tube 16. For this purpose, the pressing tool 54 is removed fromthe optic tube 16 and from the endoscope head 12. A further pressingtool 68 is pushed, in the direction of the arrow 52, through theendoscope head 12 and into the pressed-on optic tube 16, and it exertsan axial force on the proximal end area 18 of the optic tube 16.

The further pressing tool 68 likewise narrows at the distal end,although the narrowing is not in the form of a step shape but insteadextends over a concavely curved partial area of a distal end 70. Thesmallest external diameter 72 of the distal end 70 of the furtherpressing tool 68 is also slightly smaller than the internal diameter 62of the optic tube 16. The narrowing distal end 70 of the furtherpressing tool 68 spreads the proximal end 44 of the optic tube 16outwards in such a way that a shape of the proximal end 44 of the optictube 16 adapts to a shape of the distal end 70 of the further pressingtool 68. The pressing tool 54 and the pressing tool 68 can also bedesigned as one pressing tool, with which it is possible both to axiallycompress the proximal end area 18 of the optic tube 16 and also to widenthe proximal end 44 of the optic tube 16.

During subsequent insertion of optical fibres into the endoscope 10, thewidened proximal end 44 of the optic tube 16 avoids damage to saidoptical fibres.

Thereafter, the further pressing tool 68 is removed from the endoscopehead 12 in the direction of an arrow 74 (see FIG. 8).

After the pressing operation, the proximal end area 18 of the optic tube16 is also adhesively bonded to the distal end area 20 of the endoscopehead 12. For this purpose, an adhesive is applied to the outer surface40 of the optic tube 16 and/or to the inner surface 42 of the distal endarea 20 of the endoscope head 12. The adhesive bonding of the optic tube16 to the endoscope head 12 serves to seal off the connecting site ofthe two endoscope parts from external influences, such as water.

FIG. 9 shows a cross-sectional view of the distal end area 20 of theendoscope head 12 along the line I-I in FIG. 8. The proximal end area 18of the optic tube 16 is press-fitted with the distal end area 20 of theendoscope head 12. Material of the optic tube 16 engages with a form fitin the recess 28, formed as a groove 32 extending about the fullcircumference, and into the cavity 30.

1. A method for producing an endoscope, said endoscope comprising anendoscope head and an optic tube, said method comprising the steps ofproviding said endoscope head, providing said optic tube, pushing aproximal end area of said optic tube into a distal end area of saidendoscope head, press-fitting said distal end area of said endoscopehead with said proximal end area of said optic tube.
 2. The method ofclaim 1, wherein said proximal end area of said optic tube ispress-fitted by axial compressing.
 3. The method of claim 1, whereinsaid optic tube is held in an axially fixed position during saidpress-fitting, and an axial force in direction to a distal end area ofsaid optic tube is exerted on said proximal end area of said optic tube.4. The method of claim 3, wherein said axial force is provided by apressing tool.
 5. The method of claim 1, wherein said distal end area ofsaid endoscope head is provided on an inside of said endoscope head witha circumferential recess into which material of said optic tube flowswith a form fit during said press-fitting.
 6. The method of claim 5,wherein said circumferential recess is provided as a groove extendingabout a full circumference of said endoscope head.
 7. The method ofanyone of claim 1, wherein said distal end area of said endoscope headis provided with at least one circumferentially limited cavity intowhich material of said optic tube flows with a form fit during saidpress-fitting.
 8. The method claim 1, wherein a proximal end of saidoptic tube is additionally widened in a trumpet shape.
 9. The method ofclaim 1, wherein said distal end area of said endoscope head isadhesively bonded to said proximal end area of said optic tube aftersaid press-fitting.
 10. An endoscope, comprising an endoscope head andan optic tube, wherein a proximal end area of said optic tube ispress-fitted with a distal end area of said endoscope head.
 11. Theendoscope of claim 10, wherein said distal end area of said endoscopehead has, on an inner side of said endoscope head, a circumferentialrecess into which material of said optic tube engages with a form fit.12. The endoscope of claim 11, wherein said circumferential recess isdesigned as a groove extending about a full circumference of saidendoscope head.
 13. The endoscope of claim 10, wherein said distal endarea of said endoscope head has, on an inner side of said endoscopehead, at least one circumferentially limited cavity into which materialof said optic tube engages with a form fit.
 14. The endoscope of claim10, wherein a proximal end of said optic tube is widened in a trumpetshape.